Radio tuning device



NOV- 29,` 1938. w. J. SCHNELL RADIO TUNING DEVICE Filed Nov. 20, 1957 Patented Nov. 29, 1938 UNITED ys-'rii'rlas PATENT? 10mm.; f

' immo 'ruimte'nevicaY y Wiliam J. sehnen, Berwyn,r 111. Application November zo, maasaiarm. 115,695

s claims. (ci. 'x4-1o) This invention relates to a radio tuning device, more particularly of the automatic type.

Radio tuning devices of the automatic type with which applicant is familiar are of complicated mechanical or 'electrical structure; are not susceptible of ready adjustment by the user; and are relatively quite expensive; wherefore it has been found impracticable commercially to equip the cheaper and more popular priced radios with such tuning aids. Therefore it is anobject of this invention to provide a compact, emcient and readily adjustable tuning device for radio receivers or the like having a minimum number of operative parts. j`

Applicants invention further contemplates the provision of an automatic tuning device for radio receivers or .the like` .employing inexpensive and easily manufactured elements, which elements vmay be readily replaced if necessary.'-v

Other and further objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying drawing in which:

Fig. 1 is a view in perspective of a radio Vtuning device embodying the invention.

Figs. 2 to 5 are diagrammatic sketches illustrating the principle of operation of the device ofFig.`1. i

3o As shown in the drawing .forthe purpose of a housing 4 having top, bottom,. front, back'and side walls, certain of which are preferably removable to permit theassembling and ready adjustment of the elements contained therein.

An operating shaft 6 is supported within the housing 4 and `journaled in suitable fixed brackets (not shown). One end of the shaft extends outwardly of the housing forv connection to the shaft 8 of a tuning condenser. IIlof `conventional structure. The shaft '8 may be directly coupled to the shaft 8, or it may be coupled thereto by means of a flexible cable in order `that the tuning device 2 'may control the tuning condenser from a remote point.

nally on the shaftt inlongitudinallyspaced relation and each of these pulleys isadjustably secured to the shaft by a set screw I4 carried by a The shaft 2t' extends parallel to, the shaft s illustration, the radio tuning device 2 comprisesY A plurality of pulleys I2 is arranged longitudiand 1s nxedly mounted in the walls of the housing or uponsuitable brackets (notfshown). Each lever I8 isprovided with a `rearwardly extending end portion 2,.to which is secured,a Aspring 28 which urges the lever in a clockwise dlrectionto` the position shown lin.solid lines in Fig. l, ,inV which position the lever is at the top o f the slot 22.(in` the front wall of the housing. The endv of thespring 28 remote from theglever IB is an-l chored tothe bottom `or back wall of the housing. Yj Each lever I8 at its freefend outwardly of the housing carries an upstanding finger piece, key or button 30T. The lbuttons 30 may be provided with circular recessesor transparent, detachable caps for receiving indicating disks inscribed with the call letters representing certain desiredV broadcasting stations.A The leversA I8, are equal in number tothe pulleysIZ andeach lever is` connected to an` associatedlpulley by a cable,

cord, rope or wire 32 passing. about the `pulley f I2v andhaving its `free end tiedor otherwise secured to the lever I8,` an opening or fastening 34 beingprovided in the lever I8 for the purpose of facilitating the tying of the free ends ofthe cable 2thereto. In order to assure positive operation of the pulleys by the vlevers I8 and toy prevent slippage between thefcables 32 land the pulleys, each cable is fastened or clamped at its midpoint to the pulley, as for example by being looped about a screw 36 threaded into the base of the pulley groove. This clamping means mayof course be of any other desired form, as

y for-example a bifurcated resilient clamp secured to the periphery of thevpulley and extending between the flanges of the pulley to clampthe cable against movement circumferentially of the pulley groove. I i j l Partitions or the like 38 are inserted between each pulley and cable and the next adjacent pulley and cable in order torprevent interference lbetween the cablesi HThe tuningdevice havingbeen connected to the tuning `condenser `III of the .radio receiver, adjustment of the tuningdevice is accomplished as follows. The radio `receiver is tuned in the customary manner v,bymanual manipulation of thetuning condenser I0 to adesired broadcasting station. A selected lever I8 is then depressed and its associated pulley IZr'otated on the shaft s untilfbotn nigmsj'of the cable a2 become taut, f

as shown in Figi 3." In this'position the clamp 36 will liein a vertical plane passing through the axis of the shaft 8 for, as stated heretofore, the clamp, is placed at the midpoint of the cable. The setL screw I4 is then screwedin to clamp the pulley in this adjusted position. In a similar manner, the radio receiver is tuned successively to other desired broadcasting stations and the remaining levers and associated pulleys successively adjusted as described.

The tuning device having been adjusted, there will exist in each cable, when the levers Il are in their extreme upper positions, a pair of loops 40 and 42 of varying length relative to each other, depending upon the angular position of its associated clamp 35 relative to the shaft 6. It will, of course, be apparent that the clamps as-v sociated with the different cables will occupy differentv angular positions within an arc of 180 degrees, which is the limit of movement of the con-denser ill and the shafts 6 andi.

'I'he operation of the tuning device in "automatcally tuning the radio receiver to the stations to which the tuning device has been preadjusted, will be apparent from Figs. 2 to 5, which illustrate the pulleys and levers for adjusting the tuning element to its extreme positions. As shown in Figs. 2 and 3, the shaft 6 will be rotatedV in a clockwise direction to one extreme position upon depression of a lever I8. 'As shown in Figs. 4 and 5,the shaft 6 will be rotated in a counterclockwisedirection from that extreme position to its original extreme position of Fig. 2, upon depression of the lever I8 associated withanother cable 32. Other levers I8 will selectively cause rotation of the shaft 6 in like manner to other preadjuste'd'posit'ions As one lever and cable unit is operated, the relative lengths of the loops 40 and 4 2 in each cable 32 will be -varied corresponding amounts and hence each lever will at all times be operable to cause rotation of the shaft 6 to a predetermined position. Each lever will cause rotationV of the shaft in the direction determined by the flight of the cable having the shorter loop 40, and the exe tent of such rotation will be determined by the difference in the length of this loop and the loop 42. i 4

Although for purposes of explanation and to facilitate an understanding of the operation, the clamps 36 have been stated to be located at the longitudinal midpoints of the cables 32, it will be evident that they need not be so located but that each may be positioned on its cable at a point displaced therefrom a distance equal to one'- fourth the circumference ofthe pulley.

It will be evident that the cables-l2 may be 'connected directly to the shaft 6 by adjustable collars such as shown at I6, in which case the shaft 6 would be relatively enlarged or the cables 32 may be received directly in grooves in the shaft 6 and the adjustment thereof accomplished by manually pulling upon one night or the other of each cable.` i `I e Further modifications and changes may be made without departing from the spirit of the inventiomas foi-example inl place of the onepiece pulleys shown in the drawing, split pulleys, the halves of which are resiliently urged toward each Aother to frictionally clamp the cables in the pulley grooves, maybe provided.

Other changes maybe made in the form, construction and arrangement of the parts without departing fromthe spirit of the invention or sacrificing any of its attendant advantages, and the right is hereby reserved to makeall such changes as fairly fall within the scope of the following claims. V

The invention is hereby claimed as follows:

1. Ina tuning device for a radio receiver or the like, a tuning element, a shaft for operating said element, a plurality of individually operable cables, means operatively connecting said cables to turn with the shaft and at predetermined points spaced angularly about the axis of said shaft in accordance with the tuning positions of the tuning element for desired broadcasting stations, and'selectively operable means connected to said cables to cause operation of said shaft to said predetermined tuning positions.

2. In a tuning device for a radio receiver or the like, a tuning element, a shaft for operating said element, a plurality of pulleys, a plurality of cables each intermediately associated with a pulley and extending therefrom to form spaced flights, and individually operable means connected to both flights of each cable, said pulleys being individually adjustable about said shaft to predetermine the relative lengths of the flights of each cable whereby the tuning element may be moved to selectable positions to tune the receiver to predetermined broadcast stations.

3. In a tuning devicefor a radio receiver or the like, a tuning element, ashaft for operating said element, a plurality of levers pivoted at fixed points, a plurality of cables each connected to a lever and operativelyvconnected to said shaft in such manner that each cable in the unoperated position of its associated lever is provided with a plurality of loop sections varying relatively in length rin accordance with the adjusted position of the shaft, whereby said levers may be selectively operated to adjust said shaft to different predetermined positionsto tune the receiver to the selected station.

4. In a tuning device for a radio receiver or the like, a tuning element, a shaft for operating said element, a 4plurality of operating levers pivoted for individual movement about an axis parallelV to the axis of said' shaft, a plurality of pulleys spaced longitudinally of said shaft and adjustable angularly relative thereto, a plurality of cables each connected to one of said levers and intermediately associated with one of said pulleys, each cable having a pair of freely hanging loops extending between the pulley andits lever, the loop sections in each cable being of relatively different length, and means for selectively operating said levers to cause a selected cable to become taut whereby its associated pulley and the shaft will be rotated in a direction and to a position determined by the original difference in length between the loop sections of saidcable.

5. In a tuning device for a radio receiver or the like, a tuning element, a shaft for operating said element, a plurality of operating levers pivoted for individual movement in parallel planes about an axis'parallel to said shaft, a plurality of pulleys spaced longitudinally of said shaft and rotatably adjustable relative thereto, a plurality of cables each passing about a pulley and con-l nected thereto at its midpoint, each cable being connected at its opposite ends to a lever and having a pair of loop sections extending between the pulley and the lever, the loop sections in each cable being of relatively different length and means for selectively operating said levers to cause aselected cable to become taut whereby its associated pulley and the shaft may be rotated in a direction and to a position determined by the original difference in length between the loop sections of said'lcable.

6. In a tuning device for a radio receiver or the like, a tuning element, a shaft foroperating operable in parallel planes, resilient means for normally urging said levers to an inoperative position, a plurality of pulleys spaced longitudinally of the shaft, a plurality of cables each connected to one of said levers and intermediately associated with one of said pulleys, each cable having a pair'of freely hanging loop sections extending between the pulley and its lever when said lever is in its inoperative position, each pulley being selectively adjustableon the shaft to cause its associated cable to become taut when the receiver is tuned to a desired station and its operating lever is in the depressed position whereby upon selective operation of said levers the receiver will be tuned to any one of a number of desired stations.

lWILLIAM J. SCHNELL. 

